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Title: Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input, using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.
 [1] ;  [2]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Enphase Energy, Inc., Petaluma, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0038-092X
Grant/Contract Number:
AC36-08GO28308; AC36-08-GO28308
Accepted Manuscript
Journal Name:
Solar Energy
Additional Journal Information:
Journal Volume: 147; Journal Issue: C; Journal ID: ISSN 0038-092X
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
14 SOLAR ENERGY; 47 OTHER INSTRUMENTATION; direct normal irradiance; diffuse horizontal irradiance; photovoltaic system performance; model
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1416820